Manipulating ANSI colour sequences in Bash

colours.sh

#!/usr/bin/env bash
#
# Example:
#
#   . colours.sh
#
#   setColour bold underline green:black
#   echo "Hello, world!"
#   setColour reset
#

function setColour_ () {
    local base=30
    case "$1" in
        "-f")
            shift;;
        "-b")
            base=40
            shift
    esac

    local index
    case "$1" in
        "black")
            index=0;;
        "red")
            index=1;;
        "green")
            index=2;;
        "yellow")
            index=3;;
        "blue")
            index=4;;
        "magenta")
            index=5;;
        "cyan")
            index=6;;
        "white")
            index=7;;
        "default")
            index=9;;
        *)
            echo "setColour: unknown colour: $1" >&2
            return 1
    esac

    local -r code=$(( $base + $index ))
    echo -ne "\e[${code}m"
}

function setColour () {
    local i
    for i in $@; do
        case "$i" in
            "reset")
                echo -ne "\e[0m";;
            "bold")
                echo -ne "\e[1m";;
            "narrow")
                echo -ne "\e[2m";;
            "italic")
                echo -ne "\e[3m";;
            "underline")
                echo -ne "\e[4m";;
            "blink")
                echo -ne "\e[5m";;
            "inverse")
                echo -ne "\e[7m";;
            "conceal")
                echo -ne "\e[8m";;
            "strike")
                echo -ne "\e[9m";;
            "/bold")
                echo -ne "\e[22m";;
            "/italic")
                echo -ne "\e[23m";;
            "/underline")
                echo -ne "\e[24m";;
            "/blink")
                echo -ne "\e[25m";;
            "/inverse")
                echo -ne "\e[27m";;
            "/conceal")
                echo -ne "\e[28m";;
            "/strike")
                echo -ne "\e[29m";;
            *)
                if echo "$i" | grep -Fq ":"; then
                    setColour_ -f $(echo "$i" | cut -d: -f1)
                    setColour_ -b $(echo "$i" | cut -d: -f2)
                else
                    setColour_ "$i"
                fi
        esac
    done
}